Low-temperature lubricating composition



Patented Aug. 31, 1954 LOW-TEMPERATURE LUBRICATING COMPOSITION Leonard Sidney Echols, Ferguson, Mo., assignor to Shell Development Company, Emeryville, Calif., a corporation of Delaware No Drawing. Application December 23, 1952, Serial No. 327,702

3 Claims.

This invention relates to lubricants which are particularly suitable for low temperature engine operation. More specifically the present invention relates to motor lubricants normally encountered in low-temperature operating conditions associated with stop-go driving.

Oil additives which are generally found to be suitable for heavy duty lubrication are found to be unstable in light duty engines, causing the formation of very heavy deposits of lacquer and sludge under cold running conditions. Generally it is believed that this is caused by the inability of the oil additives in the presence of carbonic and sulfonic acids to resist hydrolyzers under cold running conditions. It is also increasingly evident that heavy sludges and lacquers resulting from cold operation of light duty engines are caused by contamination of the crankcase oil by fuel oxidation products.

Corrosion under cold starting conditions is also exceedingly pronounced and is primarily due to incomplete combustion of the fuel causing water to condense and enter the engine system. Additionally the gaseous combustion products, e. g. CO2, S02, S03, etc., particularly if sulfur containing fuels are used, enter the engine system and cling to the metal surfaces and, cause corrosion. These impurities lead to the formation of acids and acidic products which cause or accelerate corrosion. Water entering the engine system also causes sludge formations and emulsions which cause corrosion, sticking of engine parts, clogging, all of these factors either contribute or are directly responsible for engine wear.

Low operating temperatures, under stop-go driving conditions also result in much higher engine wear than engines which normally operate at elevated temperatures and for long periods of time without interruption. An example of stop-go driving conditions is driving an automobile in city traffic. Thus, Williams in his work on cylinder 'wear, reported in Engineer, London, Bd 155 (1933) 634/36, 660/62 states that cylinder wear at temperatures below 60 C. are exceedingly high, becoming low above 60 and remaining constant up to about 280 C.

The high rate of wear at low operating temperatures, under stop-go conditions can be attributed to a number of factors such as improper lubrication of sliding or contacting surfaces, corrosion, oil deterioration and impurities and like. At cold starting a lubricant has great difiiculty in forming a lubricating film between contacting metal surfaces because the lubricant at low temmation which does form is easily washed off by the fuel as it enters the cylinder since the lubricating film has had little if any opportunity to either form a tenacious mechanical protective film or chemically combine with the contacting surface and thereby prevent or inhibit wear.

Wear may also be attributed to oil deterioration which is caused by accumulation of impurities, e. g., fuel, water, wear particles, and dust. Fuels and particularly leaded and high sulfur fuels which have not been completely burned condense on cylinder walls, flow past the piston rings and into the crankcase, and corrode them. The deterioration products also cause oil oxidation with their accompanied deleterious by-products. Not only are the organometallic compounds in fuels responsible for engine wear but also organometallic compounds such as metal sulfonates, phosphate carboxylates, phenolates, thiocarbamates, i. e., Na, K, Ca, Ba petroleum sulfonate, dioctyl dithiophosphate, oleate, stearate, dioctyl phenate, octyl phenol-formaldehyde condensation product, which have found wide application as additives in lubricating oils. These metal ash-forming oil additives, particularly under cold operating conditions, lack desired detergent properties which is their main accent in engines operating at elevated temperatures. Additionally, ash-forming additives tend to give rise to deposits on piston crowns, on the combustion chamber walls and valve parts which come into contact with engine combustion products. Furthermore, ash-forming metal containing additives are generally rapidly depleted or give rise to oil-insoluble degradation products which cause clogging of the filter system, corrosion and wear.

It is an object of this invention to provide an improved lubricating oil composition which is particularly suitable for cold temperature operation, particularly under stop-go conditions. It is a further object of the invention to provide a much improved lubricating oil composition suitable for cold temperature operation which is resistant to wear and corrosion. It is another object of this invention to provide an improved lubricating oil which, when free from metal-containing additives, has the ability to resist oxidation and maintain clean engine conditions. It is another object of this invention to provide an improved lubricating oil containing non-metallic additives which resist depletion during use. These and other objects of this invention will be apparent from the following description and the appended claims.

peratures has less flow capacity. Any film for- It has now been discovered that the above shortcomings of ash-forming lubricants used in cold engine operations can be overcome, and an excellent lubricant produced by incorporating into a base oil minor amounts but in critical proportions of three essential non-ash forming additives which are: (a) a phosphatidic material of animal and/or vegetable origin and derivatives thereof, (b) an oil-soluble ester alcohol, and (c) an oil-soluble hydrocarbyl-substituted phenolic compound.

The phosphatidic material can be of vegetable or animal origin or a complex glyceride phosphoric acid ester such as lecithin'or cephalin or mixtures and derivatives thereof. Phosphatides may be extracted from such oils as soya bean oils or from animal tissues by any suitable means and may be used in their crude or purified form. If desired, these phosphatides may be heat treated, sulfurized, phosphorized and/or halogenated in order to increase their oil-solubility and enhance their lubricating properties.

The second primary additive of this invention is an oil-soluble monoester of a polyhydric alcohol and highly branched saturated or unsaturated acids having at least 12 carbon atoms. The alcohols may include glycerine, erythritol, pentaerythritol, mannitol, sorbitol, sorbitan, citric acid, etc, The acids may include myristoleic, palmitoleic, oleic, linoleic, linolenic, elaeostearic, licanic. ricinoleic, erucic acids, as well as unsaturated acids derived from marine and fish oils such as whale, menhaden, sardine and herring oils; rosin acid, abietic acid, naphthenic acid, dimethylcyclohexylcarboxylic acid, dimethylstearic acid, z-ethyllauric acid, and mixtures thereof.

Specific monoesters are: glycerol monooleate, glycerol monopalmitoleate; sorbitan monooleate, sorbitol monooleate, glycerol monoricinoleate, glycerol mononaphthenate, mannitan mono-2- ethyllaurate, mannitan monoleate, pentaerythritol monooleate, pentaerythritol monoester of fish oil acids, pentaerythritol mononaphthenate, polyoxyethylene sorbitol monooleate, polyoxyethylene sorbitan monooleate, etc. If desired, mixtures of these esters may be used or the esters may be modified by hydrogenation, sulfurization, chlorination, and/or polymerization.

The third essential additive of the combination is an oil-soluble hydrocarbyl substituted polar containing aromatic compound represented by the general formula:

wherein Ar is a monoor dinuclear aromatic radical, R is the same or difierent hydrocarbyl radical attached to nuclear carbon atoms, at least one of said Rs being an alkyl radical ortho in position to the YH radical and linked to the ring carbon atom by a tertiary carbon in the alkyl group having at least 4 carbon atoms, and the remaining Rs being the same as the R which is ortho to YH radical or they can be the same or different essentially alkyl, aralkyl, cycloalkyl hydrocarbon radicals having a total of at least 4 and preferably above 8 carbon atoms (8-15 preferred) and containing if desired minor proportions of polar substitutes, e. g., N02, NH2, OH, SOsH, COOH, CN, etc., Y is a chalcogen element having an atomic number of 8 to 16, namely, oxygen and sulfur (yielding the phenols and thiophenols), the radicals (YH) being attached directly to the aromatic ring, a: is an integer of 1 to 2 and y is an integer of at least 1 and preferably 3. If :1: is greater than one, then the radicals YH can be the same or different.

A preferred embodiment of additives within the class as broadly defined by formula I are 2,4,6, trisubstituted phenols represented by the formula:

wherein R1 is a tertiary alkyl radical such as tertiary butyl, tertiary amyl, and the like, preferably containing up to about 12 carbon atoms, one of R2 and R3 is a hydrocarbon radical, preferably an alkyl radical, either a primary, secondary or tertiary alkyl radical, while the other one is the same or different hydrocarbon radical as defined or an aromatic-substituted alkyl radical, more particularly an orthoor para-hydroxyalkyl phenyl-sustituted alkyl (ortho-hydroxyalkyl benzyl-) radical, being the ortho-isomer when it is R2 and the para-isomer when it is R3. When R2 or R3 is an orthoor para-hydroxyalkyl phenyl-substituted alkyl radical, respectively, the alkyl substituents thereof are chosen to be identical with R1 and. the other one of R2 and R3; thus, the compounds are alkylene bis (alkylphenols) Specific examples of compounds represented by the above formula and which are particularly useful in the practice of this invention are:

2,6-ditertiary butyl--methylphenol 2,4-ditertiary butyl-S-methylphenol 2,4-di-sec-butyl-S-tertiary-butylphenol 2,4-di-n-butyl-G-tertiary-octylphenol 2,6-ditertiary-butyl-4-benzylphenol 2,6-ditertiaryamyl-4-methylphenol 2,4-ditertiary-amyl-G-methylphenol 2,4,6-tritertiary-butylphenol 2,6-ditertiary-butyl-4-methylthiophenol 2,4-ditertiary-butyI-G-methylthiophenol 2,4-dimethy1-6-tertiary-butylthiophenol 2,4-dimethyl-6-tertiary-octylthiophenol 2,6-ditertiary-amyl--methylthiophenol 2,4,6-tritertiary-amylthiophenol 2,2'- methylene bis(4 methyl-fi-tertiary butylphenol) 2,2'-methylene bis (4,6-ditertiary-butylphenol) 2,2-methylene bis(4,6-ditertiary-octylphenol) 2,2-methylene bis( l-methyl 6 tertiary amylphenol) 2,2'-methylene bis(4-methyl 6 tertiary octylphenol) 2,2'-methylene bis(4-methyl 6 tertiary butylthiophenol) 2,2methylene bis(-octyl-G-tertiary butylthiophenol) 2,2- methylene bis(4,6 .ditertiary butylthio phenol) 2,2-methylene bis(4,6-ditertiary amylthiophenol) 2,2-methylene bis l-methyl 6 tertiary amylthiophenol) 2,2-methylene bis(l-methyl 6 tertiary octylthiophenol) (Z-hydroxy -3- tertiary-butyl -5- methylphenol) furylmethane (2 hydroxy 5 tertiary butylphenyl) furylmethane 1,1 bis(2 hydroxy 3 tertiary butyl 5- methylphenyl) isobutane bis(2 hydroxy 3 tertiary butyl 5 methylphenyl) phenylmethane V 2,2-bis(2-hydroxy -3- tertiary-butyl -5- methylphenyl) propane 1. 6 2,2-bis(2-hydroxy -3- tertiary-butyl -5- methyl- I COMPOSITION D phenyDbutane l I l Percent wt. The base for additives of this invention can Lecithin be any natural or synthetic material having lubri- 5 Pentaelythlitol 11101100169118 eating properties. Thus the base maybe a hydroy1-6-tert.-butyl-thi0phenol 0.8 carbon oil obtained from a paraffinic, naphthenic, Mineral l an Mid-Continent or Coastal stock and/or mixtures thereof. The viscosity of these oils may vary COMPOSITIONE over a wide range such as from 50 SUS at 100.F. .,.10 tto 100 SUS at 210 F. The hydrocarbon oils thin may be blended with fixed oils such as castor oil, y erol monoricinoleate 0.5 lard oil and.the like and/or with synthetic lubrio y xyethylene sorbitan monostearate 1.0 cants such as polymerized olefms, copolymers ,4,6tert.-butylphenol 1.0 of alkylene glycols and alkyleneoxides, organic Mineral Oil Balance esters, e. g., 2-ethyl hexyl sebacate, dioctyl phthalate, trioctyl phosphate; polymeric tetra- COMPOSITIONF hydrofuran, polyalkyl silicone polymers, e. g., Percent wt. dimethyl silicone polymer and the like. If de- Cephalin O 0.4 sired, the synthetic lubricants may be used as the Glycerol monoester of fish oil acids 3.5 sole base lubricant or admixed with fixed oils and C14 alkylated phenol 0.5 derivatives thereof. Mineral oil Balance The general formulations of compositions of I this invention may be represented by COMPOSITION G I Percent wt. Lecithin 0.5 Broad ted Mannitan mono-Z-ethyllaurate 25 Bang Range 2,6di-tert.butyl-4-methylphenol 0.5 glitenogcgalterial i8 8 52157 Mmeral on 7 Balance pifi hfimt saanii:::::::::::::: 0.01 to at: 0:3 to 018% COMPOSI'IIONH Base (mineral oiland/orsyntheticoil). Balance..-" Balance. I Percent wt.

Sulfurized lecithin 0.3 Glycerol monooleate 1. It is preferred that the ratio of the additives 2,6,4 di tert buty1 4 methylphenol Lo (a), (b), (c) be 1.5.1 respectively, and in the Mineral on v Balance amounts indicated above. 'T'

Preferred compositions of this invention are COMPOSITION 1 O illustrated by the following examples:

v Percent wt. COMPOSITION A Chlorinated lecithin 0.3

Pentaerythrito1 monooleate 2 Percent 2,6,4-ditertiary butyl-i-methylphenol 0.2 Lecithin Mineral oil Balance Glycerol monooleate 2- p v H 2,6-ditertiary-butyl-4-methylphenol 0.5 5 COMPOSITION J Mineral oil Balance Percent wt. COMPOSITION B Cephalin Sorbitol monoester of fish 011 acids 2.5 Percent 2,2' methylene bis(4-methyl 6-tert.-butylp lln phenol) 1.0 Glycerol monooleate Mineral O11 Balance 2,6-ditertiary-butyl-4-methylpheno1 0.2 Mineral oil B l To illustrate the pronounced improvement obtained in engine cleanliness when using composi- COMPOSITION c tions of this invention over well known lubricants Percent wt. as identified below, the following compositions Lecithin Were tested in a Vauxhall engine operating under Sorbitan monooleate 2.0 cold stop-g0 conditions for 4% hours in 25 2,2 methylene bis(4= methyl 6 tert.- cycle periods using a leaded fuel and in a Chevbutylphenol) 1- rolet engine under FL-2 cold operating condi- Mmeml nil Balanc tions:

Vaumhall engine test results Composition Engine Conditions A B D E G I II III IV V VI VII VIII Rocker cover E E E E E F F P P F P P P Push rod cover E E E E E P P P P F I P P Timing case E E E E E P F P P F r P P Bump E E E E E P P P r r P P P E==excellent. F=fair.

P-poor.

t .Chevmlet engine test resu ts Engine Conditions A B D L H J I VI I .III IV V VI VII VIII -'0 0 0 0 0 14.6 .10 12 10 14.6 8 E E E E E E l? P P P P P P I P 0llPan E E E E' E E P P P P P P P P 011 screen plugged, per

cent 0.8 0.5 5 3.5 5 3.0 Valve Cover E E E E E E P P P I? P P P P I=mineral oil.

H=mineral oil+0.5% glycerol monooleate. III=mmeral oil+0.5% lecithin. IV=mineral oil+0.5% 2,6ditert.-b1rtyl-4-methylphenol.

V=mineral oil+0.5% glycerol monooleate+0.5% 2,fi-ditert.-butyl-4-methylphenol.

VI=miueral oil+l.5% Na petroleum sulfonete.

VII=mineral oil+2.5% glycerol monooleate+1.5% Na petroleum sulionate+0;5% 2,6-ditert.-

butyl-4-methylphenol.

VIII=mineral oil+0.l% 0a salt of methylene bis-p-isooctyl phenol-{01% Ca petroleum sulfonate+ acids, extreme pressure compounds such as alkyl phosphates, friction reducing compounds such as allophanates, interfacial tension modifiers or foam reducing agents, blooming agents, soap thickeners to form grease, viscosity regulators such as acryloid polymers, detergents, etc.

These auxiliary additives may be used in amounts varying from 0.25% to about 5% by weight.

This application is a continuation-in-part of my patent application Serial No. 84,253, filed March 29, 1949, now abandoned.

I claim as my invention:

1. An ash-free low temperature lubricant consisting essentially of a major amount of a mineral lubricating oil and from 1.5 to 3.5% of glycerol monooleate, from 0.3 to 0.5% of lecithin and from 0.2 to 1% of a compound selected from the group consisting of 2,6-ditertiarybutyl-4-methyl phenol, 2,4 dimethyl 6 tertiarybutyl-thiophenol, 2,4,6-tertiarybutyl phenol, 2,2'-methylene bis(4- methyl-S-tertiarybutyl phenol) 2. An ash-free low temperature lubricant consisting essentially of a major amount of a mineral lubricating oil and from 1.5 to 3.5% of glycerol monooleate, from 0.3 to 0.5% of lecithin and from 0.2 to 1% of 2,6-ditertiarybutyl-4- methyl phenol.

3. An ash-free low temperature lubricant consisting essentially of the following formulation:

Percent 2,6 ditertiary-butyl-4-methylphenol 0.5 Glycerol monooleate 2.5 Lecithin 0.5 Mineral oil Balance References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,216,711 Musher Oct. 1, 1940 2,212,020 Hendrey Aug. 20, 1940 2,410,652 Griflinet al Nov. 5, 1946 2,482,517 Schiermeier Sept. 20, 1949 2,493,483 Francis et al Jan. 3, 1950 

1. AN ASH-FREE LOW TEMPERATURE LUBRICANT CONSISTING ESSENTIALLY OF A MAJOR AMOUNT OF A MINERAL LUBRICATING OIL AND FROM 1.5 TO 3.5% OF GLYCEROL MONOOLEATE, FROM 0.3 TO 0.5% OF LECITHIN AND FROM 0.2 TO 1% OF A COMPOUND SELECTED FROM THE GROUP CONSISTING OF 2,6-DITERTIARYBUTYL-4-METHYL PHENOL, 2,4-DIMETHYL-6-TERTIARYBUTYL-THIOPHENOL, 2,4,6-TERTIARYBUTYL PHENOL, 2,2-METHYLENE BIS(4METHYL-6-TERTIARYBUTYL PHENOL). 